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Naked mole rats are remarkable in
2 g1 [$ Q8 S4 c4 @( h0 ocombining extreme longevity with virtually complete resistance to cancer. Now a
) ~- ]4 t& C! Z& k: w3 T: t" z( Vnovel glycosaminoglycan variant that may have evolved to provide the creatures $ q, W6 E+ y& h; Q) F
with the tough, flexible skin needed for a subterranean lifestyle has been - F: \& Q8 |, Q" r, V' u
identified as a key contributor to their cancer resistance. Hyaluronan, or
+ G! k0 k4 |! i9 Y vhyaluronic acid, is a ubiquitous component of the extracellular matrix. Xiao
9 |& a3 F* f$ X% r" x3 nTian et al. observed that the culture media of naked mole-rat : v7 j0 T# K8 s; q3 v
fibroblasts becomes viscous owing to the accumulation of a thick ‘gooey’
7 h* e9 w$ c: z6 E6 M' q. Vsubstance and identified it as a high-molecular-mass hyaluronan (HMM-HA), more
) b0 B9 p1 N6 k( f% O, q3 h* bthan five times larger than mouse and human equivalents. It accumulates in naked
' d' A2 ~2 B* W9 ymole-rat tissues owing to low hyaluronidase activity and a unique form of
3 I) ~0 [/ k8 @& C6 k: ihyaluronan synthase 2. HMM-HA acts through the CD44 receptor and removal of & {* {& ]/ u% s# [6 g. k% Z
HMM-HA makes naked mole-rat cells more susceptible to transformation. This 7 f( R+ n' q5 l" S1 ?& @9 |5 F
unusual model of cancer protection suggests potential new avenues of research ) o3 ^. k3 @; n6 Y; T
into anticancer and life-extension strategies. Cover: Joel Sartore/National : E( X$ u& r/ m; B, {
Geographic Image Collection/Alamy
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发表于 2013-7-19 19:33
发表于 2013-7-19 19:42
